Why consider a piston-skirt coating?
The piston skirt guides the piston within the cylinder. A properly specified low-friction coating is intended to protect this contact surface when the lubrication film is challenged, particularly during run-in and cold starts. It may be worth considering during a carefully planned engine rebuild, when the piston and cylinder combination can be measured and evaluated together.
What can the coating do?
Graphite-containing anti-friction coatings are used on piston skirts to help reduce friction and wear in suitable applications. The result in a particular engine depends on the piston material, cylinder surface, clearances, coating process and operating conditions. General technical references do not measure the performance of a Diamond Atelier engine.
What does it not do?
A coating is not a substitute for sound pistons, correct bore geometry, suitable ring fit or adequate lubrication. It cannot be assumed to repair a worn cylinder or cure an engine fault. Nor do we promise a fixed power gain or a particular service life from the treatment alone.
How does Diamond Atelier decide?
We first identify the engine and inspect the components. Piston condition, cylinder dimensions and running clearance determine whether a coating is appropriate and which surfaces may be treated. The precise Diamond Atelier process remains proprietary; the assessment and quotation are individual to the project.
Frequently asked questions
Is this the same as rubbing graphite powder onto a piston?
No. A professional coating is a controlled surface treatment. Its preparation, adhesion and resulting film have to suit the piston and its working clearance.
Should every BMW Airhead piston be coated?
No. The decision follows measurement and the intended use of the engine. In some cases the correct recommendation is to use the parts as they are or repair them first.
Ask Diamond Atelier about piston coating for your engine.
Technical references
DuPont: graphite-filled anti-friction coating and piston applications; MAHLE: technical overview of piston-skirt coatings. These references describe the principle and do not establish a measured result for Diamond Atelier’s proprietary service.